Compressor



F. B. HUNT COMPRESSOR Filed May 25, 1934 5 Sheets-Sheet l INENTOR. Frank/1'12 5.1270222.

ATTQRNEYS T N U H B F COMPRES SOR Filed May 25, 1954 3 Sheets-Sheet 2 INVENTOR.

5 W m U. m 5

E936. F; B. HUNT.

COMPRESSOR Filed May 25, 1934 3 Sheets-Sheet 3 Patented May 19, 1936 UNETEDISTATE-S PATENT OFFICE Claims. (Cl. 230200) The present application relates to compressors,

and more particularly to compressors intended primarily for use in the liquefaction and solidification of commercial gases such, for instance, as-carbon dioxide. q 7

In commercial plants for the production of liquid and solid carbon dioxide, it is customary to cool the compressed fluid by the expansion of a portion of the liquid. In certain plants,,for instance, the gasis compressed to such an extent as to liquefy it, at a temperature somewhat above roomtemperature; and itis'then led into a primaryevaporator in which a portion of the liquid is evaporated to reduce the total pressure to approximately 300 pounds per square inch. Thence, the somewhatcooler liquid is led to, a secondary. evaporator in which a further portion of the liquid is evaporatedto reduce the total pressure to a value between 100 and 125 pounds per square inch, absolute. Thence, the cold remaining liquid is introducedinto a freezing chamber, in which-still more of the liquid is evaporated, maintaining the pressure of .75 pounds per square inch, absolute, during such evaporation, until sufiicient heat has been. removed from the remaining liquid to ef-' 5 introduced into the cycle.

, Throughout the present specificatiomgas so reintroduced into the cycle will be termed press gas, as distinguished from process gas, which is the the description proceeds.

To the accomplishment of the above and related objects, myinvention may be embodied in the form illustrated in the accompanying drawings, attention being called to-the fact, however, that trated and described, so long'as the'scope of the appended claims is not violated.

TFigl is a side elevation of a compressor connew gas introduced into, the cycle for ;the first.

detailed objects of -the invention will appear as the drawings areillustrative only,and thatchange may be made in the specific construction illus-,.

structed in accordance with the present invention;

i Fig. 2 is a longitudinal vertical section through the same;

Fig. 3 is a substantially central section, upon a much enlarged scale, of an unloading valve;

Fig. 4 is a section, upon an enlarged scale, of the right-hand end of the organization of Fig. 2;

Fig. 5 is a section, upon an enlarged scale, of the left-hand end of the organization of Fig. 2;

Fig. 6 .is an enlarged sectional view of an inlet valve; and

Fig.7 is an enlarged sectional view of an outlet valve.

It will be obvious that, during the freezing operation in the freezing chamber, throughout which it is desired to maintain a pressure within that chamber of approximately 75 pounds per square inch, absolute, it is not necessary or desirable to apply suction to the freezing chamber except in a degree sufficient to remove from the freezing chamber the gas evolved therein during the boil down. When, however, the freezing operation has been completed, it is necessary to reduce the pressure within the freezing chamber as rapidly as possible; and therefore a greater degree of suction should be applied to the chamber at that time. The device of the present application provides for such operations.

Referring more particularly to the drawings, it will be seen that I have illustrated a base l0 upon which is mounted the compressor organization of the present application. Said organi zation includes a fly-wheel mounted upon a main shaft |2 which is connected, through a pitman- [3, to a guide member l4 having a sliding bearing in frame work l5. Said guide mem her I is tied, through the medium of rods I6, to a second guide member likewise having a sliding bearing in said frame work.

To the guide member I4 is secured a piston rod I8 carrying two pistons l9 and 20. The piston I9 is mounted within a first cylinder 2| which is laterally spaced from the shaft I2, and the axis of which is perpendicular to the axis of said shaft. As is clearly shown, the rod l8 extends axially through the cylinder 2| and into a second pump cylinder 28 in which the piston 20 is mounted. The cylinder 28 is axially aligned with, and spaced beyond, the cylinder 2|.

The cylinder 2| is formed to provide an inlet chamber 22 and an outlet chamber 23; a conduit 24 leading into said inlet chamber, and a conduit 25 leading out of said outlet chamber. Valves 26 control the flow of fluid from chamber 55 22 into the pump cylinder 2 I; and valves 21 control the flow of fluid from the pump cylinder 2| into the outlet chamber 23. It will be clearly seen that the cylinder 2|, with its piston and. valves, constitutes a double acting pump.

The cylinder 28 is likewise formed to provide an inlet chamber 29 and an outlet chamber 38; a conduit 3| communicating with the inlet chamber 29 and a conduit 32 communicating with the outlet chamber 38. A valve 33 controls the flow of fluid from the chamber 29 into one end of the cylinder 28, and a valve 34 controls the flow of fluid from the chamber 29 intothe other end of the cylinder 28, said valve 34 being provided with a manually operable handle 35 whereby it may be rendered inoperative. Valves 36 control the flow of fluid from the cylinder 28 into the outlet chamber 38.

To the guide member I! is secured a piston rod 37 carrying pistons 38 and 39. The piston 38 is operatively positioned Within a cylinder 40 which is axially aligned with the cylinders 2| and 28, but which is positioned on the opposite side of the shaft I2 therefrom. The cylinder 40 is formed to provide an inlet chamber 4| and an outlet chamber 42. Flow from the inlet chamber 4| into the cylinder 48 is controlled by valves 43, the detailed construction of which is illustrated in Fig. 3 and will be described hereinafter. Flow from the cylinder 40 into the outlet chamber 42 is controlled by valves 45 which are similar to the valves 21.

A pipe 41 leads into the inlet chamber 4|, and a pipe 48 leads from the outlet chamber 42.

A fourth pump cylinder 49 is axially aligned with the cylinder 48, and is spaced therebeyond; it being clearly shown that the piston rod 31 extends axially through the cylinder 48 and into the cylinder 49, in which the piston 39 is operatively positioned. Said cylinder 49 is formed to provide an inlet chamber 58 and an outlet chamber 5|. Flow from the inlet chamber 50 into one end of the cylinder 49 is controlled by a valve 52 similar to the valve 33; while flow into the opposite end of the cylinder is controlled by a valve 53 similar to the valve 34. Flow from the cylinder 49 into the outlet chamber 5| is controlled by valves 54. A pipe 55 communicates with the inlet chamber 50 and a pipe 56 communicates with the outlet chamber 5|.

When the compressor hereinabove described is associated with the evaporators and freezing chamber hereinabove mentioned, process gas is introduced into the compressor through the pipe 24 which leads into the inlet chamber 22 asso ciated with the cylinder 2|. In the cylinder 2|, the pressure of the gas is increased to '75 pounds per square inch absolute. When the gas leaves the. cylinder 2| through the outlet chamber 23, it flows through the pipe 25, thence through a heat exchanger 51 (which is separated, by a wall 58, from a second heat exchanger 60) through by-pass 59, through heat exchanger 60, and thence through pipe 6| to pipe 62. There, this gas is joined by gas from the secondary evaporator, entering the pipe 62 at I03, likewise at a pressure of approximately 75 pounds per square inch absolute. Thence, the gas flows through the coupling 63 and pipe 54 to the pipe 55 which leads into the inlet chamber 58 associated with the cylinder 49.

When the gas leaves the cylinder 49 through the outlet chamber 5|, it flows, under a pressure of, for instance, 300 pounds per square inch,

through the pipe 56 to a heat exchanger 65, said heat exchanger 65 being separated by a wall 66 from a second heat exchanger 68. From the exchanger 65, the gas flows through by-pass 61 to and through the exchanger 68, and through the pipe 69 to the pipe 10; where it is joined by gas exhausted from the primary evaporator at approximately 300 pounds per square inch. Such gas from the primary evaporator enters the pipe 10 at the point I82.

From the pipe 10, the gas is led through pipe H and pipe 3| into the inlet chamber 29 associated with the cylinder 28; and, after compression in said cylinder 28, the fluid is discharged through the pipe 32 to a condenser, and thence to the primary evaporator.

It will be seen that the pipe 48 is connected to the coupling 63. Obviously, gas flowing through the pipe 48 into the coupling 63 should be at a pressure of pounds per square inch, absolute. Gas is led, through the pipe 41, to the cylinder 40, from the freezing chamber above mentioned. During the freezing operation, the gas will enter the inlet chamber 4| at a pressure of 75 pounds per square inch; and conse' quently it is not necessary to do any compressingin the cylinder 40. After the freezing has been completed, however, the pressure in the freezing chamber must be rapidly reduced; and during such reduction in pressure, it is necessary for the cylinder 40 to do work, both in exhausting the freezing chamber and in stepping up the pressure of the gas drawn from the freezing chamber and to be discharged into the coupling 63.

This means, of course, that the valves 43 must be held open during certain phases of the operating cycle, whereby the cylinder 40 will be unloaded; but that they must be thrown into operation to load the cylinder 48 during other phases of the cycle.

For this purpose, I have found a valve of the type illustrated in Fig. 3 to be highly advantageous. Within a port in the wall of the cylinder 4!] there is mounted a plate 8| having grating bars 82 defining a plurality of parallel passages 83. Clamped to said plate 8| is a second plate 84 likewise having grating bars 85 defining parallel passages 86 which are staggered with respect to the passages 83. Between the plates 8| and 84 are gripped reed-like fingers 81 of resilient metal, said fingers being biased to a position in which they close the passages 86.

Obviously, a pressure difierential between the two sides of the combined plates 8| and 84 will result in movement of the fingers 81 into open or closed positions, depending upon the direction of the pressure difierence.

A dome 88 is secured to the outer wall of the inlet chamber associated with the cylinder 48, and said dome adjustably carries a, stem 89 which may be secured in place by a lock nut 90. Said stem carries a bonnet 9| which cooperates with a casing 92 within the said inlet or outlet chamber to form a closed cylinder 93 within which is reciprocable a piston 94 which is normally urged, by a spring 95, toward its uppermost position, as viewed in Fig. 3. Said piston 94 carries a stem 96 which terminates in an enlarged portion 91 carrying a plurality of projecting fingers 98 which are positioned in registry with the passages 86. It will be clear that the plates BI and 84 are secured to the casing 92 by means of bolts 99.

A tube I08 extends through the stem 89 and communicates with the interior of the cylinder 93. Through said tube fluid under pressure may beiintroduced into saidcylinder to move the piston 94 against the tendency of the spring 95, thereby projecting the fingers 98 .through the passages Q6, whereby the fingers 81 are positively moved, and held, out of closing relation with the passages 86.

It will be clear that the tube H10 associated with each of the valves t3 and 45 may be so associated with the freezing chamber that the pistons 9d of said valves will be automatically operated in response to pressure changes within said freezing chamber; and it will also be clear that the arrangement may be such that, as the pressure in the freezing chamber is reduced, the fingers 93 of the several valves 43 and 45 will be successively withdrawn to render said valves successively operative.

In Fig. 61 have illustrated, in detail, the structure of valves like valves 26, 33 and 52. It will be seen that the valve 26$! comprises a casing or shell 26! open at both ends, and receiving, at one end, a threaded spider 262 formed to provide an inwardly-facing tapered seat 263 with which cooperates a correspondingly shaped valve head 2% carried on a stem 265. Said stem is slidably guided in the tubular shank 266 of the spider .252, said shank terminating, at its upper end, in an enlarged threaded closure 261 threadedly received in a suitable aperture in the outer shell of one of the pump organizations. A spring 268 surrounds the stem 265 within the shank 266, being secured therein by a plug 259, and resiliently urges the valve head 2% against its seat 263. Obviously, the valve 264 will open in response to an intake movement of the pump piston, and will be closed by the spring 268 whenever the pressure within the cylinder controlled thereby approximates equality with the pressure outside that cylinder.

In Fig. 7, I have illustrated in detail a valve similar to valves El, 36, 45 and 54. It will be seen that the valve 210 comprises a shell 2H formed to provide an outwardly facing tapered valve seat 272 with which cooperates a correspondingly shaped valve head 213. end of the shell 2H threadedly receives a spider 214 having a tubular shank 2'55 terminating, at its outer end, in an enlarged threaded closure 2'36. A stem 21'! of the valve head 213 is slidably received within the tubular shank 215, and a spring 218 is coiled around said stem within said tubular shank and resiliently urges said valve 213 into contact with its seat.

The valves 3d and 53 are quite similar to the valve 25%, except that manually operable means are provided for holding the valve heads positively out of contact with their respective seats in opposition to the tendency of the springs associated with said heads.

In practice, I find the following arrangement to be best. During the period of supply of liquid to the freezing chamber, and during the boildown period, gas evolved in the freezing chamber and flowing toward the cylinder 40 will be at a pressure not less than '75 pounds per square inch, absolute. Since it is desired to supply that gas to the coupling $3 at a pressure of approximately '75 pounds per square inch, absolute, it is clear that the cylinder 46 will not be required to do any work during that period. Therefore, both valves 43 are held open during that period. As the freezing step nears completion, the pressure in the freezing chamber begins to drop; and I prefer to arrange the control mechanism for the valves The outer 43 in such manner that, when the pressure in the freezing chamber drops below 75 pounds per square inch, absolute, one of the valves 43 will be drawn into operation, so that one end of the cylinder 40 will begin to pump to raise the pressure of gas supplied to the cylinder 40 and to discharge it to the coupling 63 at '75 pounds per square inch, absolute. Then, when the pressure in the freezing chamber drops to approximately 45 pounds per square inch, absolute, the other valve 43 Will be automatically thrown into operation so that both ends of the cylinder at will operate to exhaust the freezing chamber and to boost the pressure of the gas introduced into said cylinder. When the pressure in the freezing chamber reaches atmospheric pressure, both valves 43 will again be automatically opened.

The heat exchanger 51 may be fed with refrigerating fluid through the circulating pipes 12 and 13. Similarly, circulating pipes 14 and T5 are associated with the exchanger 60; circulating pipes 16 and l! are associated with exchanger and circulating pipes l8 and i9 are associated with the exchanger 68.

At I0! I have illustrated a hand wheel for the adjustment of a clearance pocket at the end of the cylinder 49.

I claim as my invention:

1. A compressor comprising a plurality of pump cylinders, pistons in said cylinders, means for operating said pistons, conduits for leading fluid serially through said cylinders, another pump cylinder, a piston operatively received within said last-named cylinder and driven in unison with one of said first-mentioned pistons, means for supplying fluid to said last-named cylinder, means for conducting the fluid exhausted from said last-named cylinder into a conduit providing communication between two of said firstmentioned cylinders, and means operable, at times, to hold open the intake valves of said lastnamed cylinder.

2. A compressor comprising a main shaft, a plurality of axially aligned pump cylinders, a piston in each of said cylinders, means operatively connecting all of said pistons with said shaft whereby rotation of said shaft results in simultaneous reciprocation of said pistons, conduits for leading fluid serially through said cylinders, another pump cylinder axially aligned with said first-mentioned cylinders, a piston in said lastnamed cylinder and operatively connected to said shaft to move with said first-mentioned pistons, and a conduit leading fluid discharged from said last-named cylinder into a conduit providing conmiunication between two of said first-mentioned cylinders.

3. A compressor comprising a main shaft, a plurality of axially aligned pump cylinders, a piston in each of said cylinders, means operatively connecting all of said pistons with said shaft whereby rotation of said shaft results in simultaneous reciprocation of said pistons, conduits for leading fluid serially through said cylinders, another pump cylinder axially aligned with said first-mentioned cylinders, a piston in said lastnamed cylinder and operatively connected to said shaft to move with said first-mentioned pistons, a conduit leading fluid discharged from said lastnamed cylinder into a conduit providing communication between two of said first-mentioned cylinders, and means operable, at times, to hold open the intake valves of said last-named cylinder.

4. A compressor comprising a main shaft, a

first pump cylinder laterally spaced from said shaft and having its axis perpendicular to the axis of said shaft, a second pump cylinder axially aligned with said first cylinder and spaced beyond said first cylinder, a third pump cylinder axially aligned with said first cylinder and positioned on the opposite side of said shaft therefrom, a fourth pump cylinder axially aligned with said third cylinder and spaced therebeyond, a piston rod extending axially through said first cylinder and into said second cylinder and carrying a piston within said first cylinder and. a piston within said second cylinder, a piston rod extending axially through said third cylinder and into said fourth cylinder and carrying a piston within said third cylinder and a piston within said fourth cylinder, means operatively connecting said shaft to drive said piston rods, a conduit leading into said first cylinder, a conduit leading from the outlet of said first cylinder to the inlet of said fourth cylinder, a conduit leading into said third cylinder, a conduit leading from the outlet of said third cylinder into said second-mentioned conduit, and a conduit leading from the outlet of said fourth cylinder to the inlet of said second cylinder.

5. A compressor comprising a main shaft, a first pump cylinder laterally spaced from said shaft and having its axis perpendicular to the axis of said shaft and having an inlet and an outlet, a second pump cylinder axially aligned with said first cylinder and spaced beyond said first cylinder and having an inlet and an outlet, a third pump cylinder axially aligned with said first cylinder and positioned on the opposite side of said. shaft therefrom and having an inlet and an outlet, a fourth pump cylinder axially aligned with said third pump cylinder and spaced therebeyond and having an inlet and an outlet, valves for all of said inlets, valves for all of said outlets, a piston rod extending axially through said first cylinder and into said second cylinder and carrying a piston Within said first cylinder and a piston within said second cylinder, a piston rod extending axially through said third cylinder and into said fourth cylinder and carrying a piston within said third cylinder and a piston within said fourth cylinder, means operatively connecting said shaft to drive said piston rods, a conduit leading to the inlet of said first cylinder, a conduit leading from the outlet of said first cylinder to the inlet of said fourth cylinder, a conduit leading to the inlet of said third cylinder, a conduit leading from the outlet of said third cylinder into said second-mentioned conduit, a conduit leading from the outlet of said fourth cylinder to the inlet of said second cylinder, and means operable, at times, to hold the inlet valve of said third cylinder in open position.

6. A compressor comprising a main shaft, 2. first pump cylinder laterally spaced from said shaft and having its axis perpendicular to the axis of said shaft and having an inlet and an outlet, a second pump cylinder axially aligned with said first cylinder and spaced beyond said first cylinder and having an inlet and an outlet, a third pump cylinder axially aligned with said first cylinder and positioned on the opposite side of said shaft therefrom and having an inlet and an outlet, a fourth pump cylinder axially aligned with said third pump cylinder and spaced therebeyond and having an inlet and an outlet, valves for all of said inlets, valves for all of said outlets, a piston rod extending axially through said first cylinder and into said second cylinder and carrying a piston within said first cylinder and a piston Within said second cylinder, a piston rod extending axially through said third cylinder and into said fourth cylinder and carrying a piston within said third cylinder and a piston within said fourth cylinder, means operatively connecting said shaft to drive said piston rods, a conduit leading to the inlet of said first cylinder, a

conduit leading from the outlet of said first cylinder to the inlet of said fourth cylinder, means associated with said last-named conduit for cooling fluid flowing therethrough, a conduit leading to the inlet of said third cylinder, a conduit leading from the outlet of said third cylinder into said second-mentioned conduit, a conduit leading from the outlet of said fourth cylinder to the inlet of said second cylinder, means associated with said last-named conduit for cooling fluid flowing therethrough, and means operable, at times, to hold the inlet valve of said third cylinder in open position.

FRANKLIN B. HUNT. 

